Session = HibernateSessionFactoryMaster.getSessionFactory().openSession();
session.beginTransaction();
session.save(user);
session.getTransaction().commit();
session.close();

<hibernate-mapping>
<class name="User" table="User" lazy="false">
    <id column="Id" name="Id">
      <generator class="guid"/>
    </id>
    <property name="login"/>
   
    <list cascade="all" lazy="true" name="loginD" table="LoginData">
      <key column="userId"/>
      <list-index column="idx"/>
      <one-to-many class="LoginData"/>
    </list>
</class>

<class name="LoginData" table="LoginData" lazy="false">
    <id column="loginDataId" name="loginDataId" unsaved-value="0">
      <generator class="guid"/>
    </id>
    <property name="login"/>
    <property name="password"/>
    <property name="roleId"/>
  </class>

</hibernate-mapping>